Cardiac resynchronization therapy: implantation tips and tricks.

Cardiac resynchronization therapy has been shown to improve quality of life and mortality in selected, subgroup of systolic heart failure patients with left ventricular (LV) dyssynchrony. However, LV lead implantation can be difficult or ultimately unsuccessful in 10 to 15% of patients. The reasons for difficult LV lead implantations are coronary venous system related issues (failure to access coronary venous system and anatomic variations in the coronary veins), extensive scar tissue in the target region for LV pacing, phrenic nerve stimulation, and LV lead instability. The aim of this review is to address the potential causes of difficult LV lead implantations and summarize the solutions for these challenging implantations with the advent of new technologies, better tools, and improved techniques.